Actually, I think (and current acadrmic thinking backs this up) that if someone is more fluent when alone, then the only thing that will lead to gaining control of your speech in a *sustainable* way is to stop trying so hard to hide it. You should try it and see how amazingly effective it can be. Its hard work that can be intimidating for some. But It’s free, accessible to everyone, and if you carefully create a risk-free situation, there’s very little to loose.